CDK4-pRB-E2F1通路是Aβ_(1-40)诱导皮层神经元凋亡的可能途径

CDK4-pRB-E2F1 pathway may mediate Aβ_(1-40)-induced apoptosis in rat cortical neurons

目的 :探讨 β淀粉样肽1-40 (beta -amyloidpeptide1-40 ,Aβ1-40 )诱导大鼠皮层神经元凋亡的可能分子机制。方法 :以 4 0mg/L的Aβ1-40 诱导离体培养的大鼠皮层神经元凋亡 ,流式细胞仪及免疫印迹方法检测细胞周期相关的周期依赖性激酶 4 (CDK4 )、磷酸化的视网膜神经胶质瘤蛋白 (pRB)水平 ;RT -PCR技术检测E2F1mRNA表达水平 ;荧光分光光度计检测半胱氨酸基天冬氨酸特异性蛋白酶 3(caspase - 3)活力 ;观察在Aβ1-40 诱导凋亡过程中是否伴随上述指标的变化。结果 :①CDK4、磷酸化pRB水平在Aβ1-40 作用后 2 - 4h显著升高 ;②Aβ1-40 孵育 3h后皮层神经元E2F1基因表达上调 ;③Aβ1-40 作用 12 - 2 4h后caspase- 3活力明显升高。结论 :CDK4 -pRB -E2F1信号转导通路可能在Aβ1-40 诱导的大鼠皮层神经元凋亡中起主要作用。

AIM: To study the possible molecular mechanism of beta-amyloid peptide_ 1-40 -induced apoptosis in rat cortical neurons. METHODS: 40 mg/L beta-amyloid peptide_ 1-40 (Aβ_ 1-40 ) was used to induce apoptosis in cultured rat cortical neurons. The level of CDK4, phosphorylated pRB were detected by flow cytometry and immunoblotting; RT-PCR was used to examine the mRNA expression of E2F1 while fluorescent spectrofluorometer was used to measure caspase-3 activity. All of the above study was designed to observe whether the level of CDK4, phosphorylated pRB and E2F1 mRNA expression could be affected by Aβ_ 1-40 . RESULTS: (1)The level of CDK4, phosphorylated pRB increased markedly 2-4 hours after treatment with Aβ_ 1-40 , and caspase-3 activity elevated remarkably 12-24 hours after treatment with Aβ_ 1-40 ; (2) E2F1 mRNA expression was upregulated 3 hours after incubation with Aβ_ 1-40 . CONCLUSION: Aβ_ 1-40 may induce apoptosis in rat cortical neurons in a manner dependent on CDK4-pRB-E2F1 pathway.